At least nine foreign workers are missing after Islamic State militants attacked a Libyan oil field, officials said Saturday.

Security forces have retaken the al-Ghani field, which the militants attacked Friday, Libyan security officials said. Several guards were killed in the attack.

Oil industry officials said at least nine foreign workers had gone missing after the attack, two from Europe. Czech Foreign Minister Lubomir Zaoralek said a Czech national was among them. He said the foreigners might have been kidnapped. The Austrian foreign ministry confirmed that an Austrian worker also was missing. The names of those missing have not been disclosed.

No one has made any demands yet for the return of the missing workers.

Libya has been increasingly unstable since longtime dictator Moammar Gadhafi was overthrown and killed in 2011. Fighting escalated in August when the elected government and parliament were forced to relocate outside Tripoli. Islamic extremists who took over the capital have established a rival government.

Western nations are backing U.N.-mediated talks to end the crisis, fearing that radical Islamic groups could use the unrest to gain a foothold in Libya. The world body is working toward establishing a permanent cease-fire between the warring factions and redirecting Libya on the path to democracy.

On Saturday, the U.N. announced that progress had been made in the latest round of talks in Morocco and that the sides would return to Rabat for more talks Wednesday.

Since 2014, Islamic State has killed hundreds of civilians in Iraq and Syria and claimed responsibility for the deaths of several foreigners. It has publicized graphic videos of those killings on social media.

Last month, it released footage of the immolation death of a Jordanian pilot shot down over Syria, as well as pictures purporting to show the beheading of two Japanese hostages.